The Clinical Core operates as the unit of the Oregon Alzheimer's Disease Center (OADC) with responsibility for identification, recruitment, characterization, and follow-up of populations of well-characterized subjects for clinical research. In keeping with the OADC focus, the Clinical Core is organized to optimize research, leading to better defining normal aging and the transitions to mild cognitive impairment (MCI) and early dementia. In order to fulfill this mission, the Clinical Core completes systematic assessments resulting in standardized diagnoses of the research cohorts, which are then entered into the relational database of the OADC. Many types of data are collected in order to be responsive to current and anticipated needs of the research community: clinical histories, neurological examinations, MRI brain images, neuropsychological and behavioral assessments, and laboratory data. The Clinical Core works closely with the other cores of the Center to ensure tissue donations (Neuropathology Core), characterization of genetic associations (Genetics Core) and smooth transfer, entry, storage and retrieval for analysis of the data (Data Management and Statistics Core). The Clinical Core faculty acts as an important knowledge resource, participating in Education and Information Transfer Core educational activities and programs. The Clinical Core is dedicated to on-going evaluation of its identified cohorts and to ensuring that subjects are not lost to follow-up. Several groups form a particular focus of the Clinical Core: 1) early Alzheimer's disease and related dementias;2) non-cognitively impaired or MCI elderly at high risk for developing dementia, emphasizing the oldest old;and 3) subjects reflecting social and racial diversity (African American, Native American, and isolated rural populations) through the Satellite program. These subject groups and the research resources they create are used for a wide range of studies, including the natural history of aging without cognitive impairment, the genetics of incipient dementia, biomarkers of underlying disease, and alternative treatment or prevention regimens for cognitive decline. Implicit in this core is a fundamental commitment to research collaboration both within our local pool of talented investigators, as well as with our colleagues among the larger community of scientists at other ADC's and other relevant research institutions.